man inspecting air vent

Why Is a Musty Odor Coming Out of My AC Vents?

Have you ever turned on your HVAC system only to discover a musty, “dirty sock” smell coming out of the air vents? This problem is more common than most people think. Below, we’ll explain what can cause this unpleasant odor and the steps you can take to avoid this issue.

Am I Smelling Mold?

Most likely, yes, you are smelling mold or mildew. While removing heat from your indoor air, your air conditioner also dehumidifies it. This means that your air conditioner contains a lot of moisture that it has drawn out from your indoor air.

What does this have to do with mold? Well, moisture is a necessary “ingredient” for mold growth. The other things mold needs are oxygen, warmth (about 80 degrees Fahrenheit), darkness, and food, which can be something as basic as the dust collecting in your HVAC system.

Where Does Mold Grow in Heating and Cooling Systems?

Mold can grow wherever moisture and dust are both present in our HVAC system. Our technicians typically find mold in the following areas:

  • The evaporator coil. This part of your AC is located indoors and draws heat and humidity out of your indoor air. If the coil goes too long without maintenance, it can get extremely dirty. The dust and condensation on the coil, combined with the warm air being blown over it, can provide a suitable environment for mold growth.
  • The drain pan. The condensation your evaporator coil collects drips down into the drain pan. From there, it leaves your home through a pipe called the condensate drain line. If a clog forms in the drain line, the drain pan will accumulate standing water (and eventually overflow). If coated with enough dust and grime, mold can start growing in the pan and drain line.
  • Leaky air ducts. Under proper conditions, moisture shouldn’t be entering your air ducts. However, leaks from gaps or rips in the ductwork can allow excess humidity inside. If your air ducts are already coated in dust, conditions might be warm enough to foster mold growth in your ductwork.

How Do I Prevent Mold Growth in My HVAC System?

Routine preventative maintenance is the best wait to prevent mold from growing in your system’s indoor unit. During the appointment, the technician will flush out the condensate drain line and clean the dust and grime off your equipment’s components, eliminating that mold food source.

Professional air duct cleaning can help you avoid mold growth in your HVAC system’s ductwork. Using high-quality equipment and mold inhibitors that you can’t find in stores, a licensed HVAC contractor can clean the nooks and crannies of your air ducts thoroughly to prevent future mold problems.

At Tom's Mechanical, Inc. we offer a wide range of top-notch HVAC and indoor air quality services throughout Tarrant County. Give us a call today at (972) 388-3669 or contact us online.